Test obfuscated IPs only on Linux.

tests/__init__.py

@@ -17,6 +17,7 @@
 import signal
 import subprocess
 import os
+import sys
 import socket
 from nose import SkipTest
 from contextlib import contextmanager
@@ -103,6 +104,14 @@ def has_posix ():
 need_posix = _need_func(has_posix, "POSIX system")
 
 
+@memoized
+def has_linux ():
+    """Test if this is a Linux system."""
+    return sys.platform.startswith("linux")
+
+need_linux = _need_func(has_linux, "Linux system")
+
+
 @memoized
 def has_clamav ():
     """Test if ClamAV daemon is installed and running."""

tests/test_network.py

@@ -19,7 +19,7 @@ Test network functions.
 """
 
 import unittest
-from tests import need_posix, need_network
+from tests import need_posix, need_network, need_linux
 import linkcheck.network
 from linkcheck.network import iputil
 
@@ -37,10 +37,11 @@ class TestNetwork (unittest.TestCase):
         ifc.getInterfaceList()
 
     @need_network
-    @need_posix
+    @need_linux
     def test_iputils (self):
         host = "www.golem.de"
         ips = iputil.resolve_host(host)
+        self.assertTrue(len(ips) > 0)
         obfuscated = iputil.obfuscate_ip(ips.pop())
         self.assertTrue(iputil.is_obfuscated_ip(obfuscated))
         hosts = iputil.lookup_ips([obfuscated])